Circuit arrangement for use in the transmission of signals



Feb. 20, 1923. 1,446,434

W. SCHAFFER ET AL CIRCUIT ARRANGEMENT FOR USE IN THE TRANSMISSION OF SIGNALS Filed Aug. 18, 1922 Patented Feb. 20, 1923.

UNiTED STATES WALTER SCHAFFER AND FRITZ KRUSCHINSKY, 0F BERLIN,

GERMANY.

CIRCUIT ARBANGEMET FOB US IN THE TRANSMISSION' ,OFl SGNALS.

Application led August 18, 1922. Serial No. 582,614.

To aZl'w/Lom t may concern ,V I

Be it known that we, lVAL'rEniSCHAFFnR and Dr. FRITZ KRUSCHINSKY, citizens of the Republic of Germany, and residents of Hallesches Ufer 12/13, Berlin, Germany, have invented new and useful Improvements in Circuit Arrangements for Use in the Transmission of Signals, for which an application, No. G. 54,535, was filed in Germany on August 5, 1921, and of which the following is a specification accompanied by drawings.

It is well known that the resistance of an alternating current circuit may be varied within wide limits by inserting an iron core choke coil into theA circuit and more particu- Alarly by varying the directcurrent premagnetization of the coil. The present invention relates to special means of this character which serves particularly for controlling the alternating current feed of cathode t-ube senders (transmittingr tubes).

In the drawing,

Fig. 1 is a diagrammatic representation of a` circuit arrangement embodying the invention, and

F ig. 2 is a diagrammatic iepresentation of a circuit arrangement of modified form.

ln accordance with t-he present invention and as shown in the drawing, the choke coil Dr is inserted in the generator circuit in series with the transformer T, the choke coil being provided with a winding Gd for the purpose of direct current premagnetization. l `urthermore, the alternating current circuit of the generator G comprises a special transformer HT the secondary winding of which is in a circuit including a rectifier (il of any desired type, which converts the alternating current induced in the secondary winding of the transformer HT into 'directcurrent. The direct current in thefsecondmentioned circuit varies in accordance with the current load of the generator G and is connected to the premagnetizing winding Gd of the choke coil Dnpreferably through a choke coil d1. If the load on the secondary of the main transformer T is varied, then the current load of the generator G is varied accordingly, which in turn causes variation of the direct current delivered by the rectifier to the premagnetization winding Gd and thereby also of the apparent resistance of the coil Dr. The variation occurs in such a manner that when the load on the transformer T is decreased the apparent resistance of coil Dr is increased, and when the load is increased, the resistance isdecreased. choke coils, transformers,vetc., the changes in potential in the circuit of the generator G, which ordinarily result from changes in the load on the circuit may be exactly neu-l tralized by the variation in the apparent resistance of the choke coil Dr. In other words, by properly dimensicning the elements of the generator'. and direct current circuits, constant potential may -be caused to exist, for example, at the terminals of the resistance R independently of changes in its value or at points A, B of the transformer T independently of its load. The resistance R is intended to represent the resistance of.

the transmitting tube. This circuit arrangement may be used to good advantage for various purposes, e. g. (1) if a further rectifying arrangement is connected to the secondary winding of the-transformer T- for the purpose of feeding a tube sender,and if the tube sender is operated inthe well known manner through the agency ofa socalled grid key, that is, a key in its grid filament circuitfor opening and closing it, then, by means .of the above described a-rrangement, the potential supplied to the; tube ma be caused to remain constant independent y of the open or closed condition of the key; (2) if the auxiliary means used in the circuit are so proportioned that the alternating potential at the points A, B of the transformer is constant independently of the load on the transformer, then it will vbe possible to branch off a conductor from points A, B leading to the he( ting filaments, e. g. of the above described se der tubes. In this case the heating current remains constant independently of the operation of the key, whereas the potential of the anode direct current fed to the tubes varies within certain limits due to the potential losses in the secondary winding of the transformer T, etc. If, however, it is desired that the direct current supplied be also maintained con# stant, thenthis may be accomplished by the double use of the above described elements.

The drawing also represents a further embodiment of the circuit arrangement 4 which consists in providing a coil S on the core carrying the choke coil D1' and the direct current premagnetization winding Gd. This' coil may, for instance,be use for the purpose of making possible the actuation of the sender by means of the main By properly dimensioning the lll v v incense' l current. lt the coil is connected in series with a key 'la and a direct current source ld, then, by actuating the key To, the premagnetization oit the choke coil Dr 'and therefore its apparent resistance may be varied Within certain limits and the control ot' the sender thereby accomplished. rll`his method ot controllingthe sender by interruption of the main current may be used instead oit interrupting the grid circult as mentioned above. Obviously in both cases the key 'la may be replaced by an arrangement used in telephony, e. g. by a cathode l hy speech. should he noted the Whole arrangement is adjustable to the transformer lrl'li4 lor the purpose of making possible the ldesited tuning. This may tor instance be accc v3lished in such a lmanner that a variable ce is connected in parallel with the primary or secondary ot the transformer if* or premagnetizing Winding Gol.

.eed ci ifaryinfvf the preniagnetization ci the choke coil byl the rhythm of the key lar . t iephone through thel agency ot' the coil another means may be used for this purpose. -This consists in using a valve V, l? ig. a. provided with a grid, in the place of the rectifier kG? in the direct current circuit. its

well known, such valves operate as rectiiers. However, the direct current that they permit to pass may he made dependent on the grid potential. li the grid potential of the rectii'ying tube is varied in the Well known manner by actuating the key K, then, the premagnetization of the coil D7' Will also be varied. i

Furthermore, in the case of speech or key rhythm the premagnetization. may be varied in such a manner that the current supply by auxiliary transformer H'l is controlled by means or suitable rectiliers.

lla-ving described our invention, what We claire is:

l. A circuit arrangement comprising an alternating current generator, an inductive resistance device in the circuit of said generator including a choke coil, a transformer having its primary in the generator circuit and its secondary ina direct current circuit for magnetizing the core of the choke coil,

and a rectier in the direct current circuit,`

said generator circuit and said direct current circuit having their elements including the transformer and the choke coil so dlmensioned and coupled as tomaintain a com stent potential in the generator circuit regardless of variation in the load on said circuit.

2. An arrangement for controlling the pol tential of a cathode tube sender, comprising an alternating current generator, a choker.

coil in the circuit of said generator, a trans-l tuhe the grid potential or which is moduiormer adapted to be connected to the tube sender and having its primary in said generator circuit, a second transtormeralso having its primary in the generator circuit and having its secondary in va direct current `circuit tor magnetizingthe choke coil, and a rectiier in said direct current circuit, said generator circuit and saiddirect current circuit having their elements including thetransformer and the choke coil so dimensioned and coupled as to cause the `notential v supplied to the cathode tube to remainxconthird nec-ted with said inductive resistance dei/'ice to vary the resistance of said device and means for controlling the dow ot current in said third circnitior the transmission of signals.

4i. l circuit arrangement tor use in the transmission ot'signals, comprising an 4alternating current' generator, an 1nductiVeresistance device in the circuit or said generator including a choke coil, a transformer having its primary in the generator circuit and its secondary in a direct current circuit for magnetizing the core or the'choke coil, and a cathode tube in the direct current circuit or rectitying the current induced into said circuit from the transformer and varyying the premagnetization of said inductive resistance device so as to enable a signal to be given by modulation ofthel current in the main generator circuit.

rA circuit arrangement for use in the transmission ot signals, comprising an alternating current generator, an inductive resistance device in the circuit of said generator including a choke coil,a transformer haviccV ing its primary in the generator circuit andl v' l itssecondary in a direct current circuit for magnetizingthe core of the chokecoil, and a cathode tube in the direct current circuit for rectifying the current induced into said "y circuit from the transformer, said cathode tube being provided with a grid whereby a signal can be givenvby varym the potential impressed on the grid and th ing the pre-magnetization of the. .inductive resistance device and the current in the main generator circuit.

WALTER sonarrngn. ns. ritira KRUSCHINSKK ereby vary; 

